In the process of manufacturing a part, such as a stamped sheet metal panel where it is important that the surface be precisely shaped, it may be beneficial to verify and, if necessary, to accurately correct (rework) the design of the surface or of the manufacturing process. To verify the part, the surface shape is compared with design specifications. These comparisons may be made by technicians who view the parts in “green rooms,” areas of controlled lighting, in order to discover defects or distortions in the appearance of the part. The technicians are grading the parts subjectively, according to individual experience and individual measures of acceptable variations in appearance.